the work that your soul does is accomplished here in physical manifestation.
so, that is the setting for the dream, this physical world. your co-workers
were engaged in respectable professions, yet their attitudes appeared flippant
and ridiculous to you. it could be that they were simply 'carefree' and it was
your attitude of seriousness which had made them appear to be silly.
although you've described them as "mocking" and "pretending [to] care",
i don't get the sense that they were truly malicious or intending of harm.
[in fact, they may have been acting in furtherance of your best interests.]
to have lost your voice would indicate an inability to make your desires
known to the world... their remedy for that was to provide you with a
garment in keeping with their 'carefree' attitude... which carried with it
those scorpions. the scorpions had stung you, which effectively delivered
their 'poisonous' thoughts into your bloodstream [providing you with some
new ideas to incorporate into your system]. that you were stung on the arms
[appendages of manipulation] is suggesting that your ability to make your
wishes known to the world may return through your skills of adjusting
physical reality to suit your wants... with the mantle of frivolity being
visible to any onlookers. (people may think you're behaving in a silly
manner while you are enacting positive changes in the world.)